A rotary machine includes a rotatable rotor, buckets radially mounted on and spaced apart about the rotor, a stationary stator/casing disposed about and radially outward from the rotor defining an annular gap between the casing and tips of the buckets, and an abradable seal member provided to the bucket tip portions and disposed within the annular gap such that during differential growth of the rotor and buckets relative to the casing the seal member abrades in response to contact with a base seal member provided to the stator casing. Thereby, clearance between the stator casing and bucket tips is minimized between the moving bucket tips with the stator casing.
A conformal seal (20) for sealing air flow between a cooling airflow path and a hot gas flow path within a combustion turbine engine. The conformal seal (20) may be fitted within cooperating side slots of adjacent vane segments (10) within the combustion turbine engine. The conformal seal (20) may include an elongated metallic substrate (22, 40) forming an upper surface and a lower surface. A conformal coating (26, 44) may be deposited over one or both surfaces of the substrate (22, 40). The conformal coating (26, 44) may be deposited to a depth so that a point contact between the conformal coating (26, 44) and respective interior walls of the side slots wears the conformal coating (26, 44) to establish surface area contact there between. The surface area contact improves a sealing function between the conformal coating (26, 44) and the respective interior walls during operation of the combustion turbine engine.
An abradable seal is provided to improve turbine performance by physically reducing the clearance between a flange portion of the nozzle and an opposed angel wing/seal plate member of the bucket. The provision of an abradable seal also mitigates angel wing/seal plate tooth or fin wear by providing for abradable contact without metal to metal hard rub.
